Legendary "royal star" was an actual supernova

In 1660, Britain restored the monarchy after a decade of Oliver Cromwell's puritanical dictatorship. Charles II's supporters pointed out that his birth was marked by a glorious noon-day star, proving his divine right to rule...and that wasn't necessarily just propaganda.

Royalist pamphleteer Edward Matthew offered this predictably flowery description of the star in 1661, the year of Charles II's coronation:

"The Most Glorious Star... shining most brightly in a Miraculous manner in the Face of the Sun. Never any Starre [had] appeared before at the birth of any (the Highest humane Hero) except our Saviour."

Yes, this "royal star" pretty much proved Charles II was only a notch below Jesus. Under those circumstances, a country would be crazy to not make him king, right? Considering Charles's father, Charles I, had been kicked off the throne and decapitated in 1649, this royal star was just the sort of spectacular proof the United Kingdom needed to accept Charles II's renewed claim to the throne.

It seems like far too good a story to be true, and historians have generally dismissed it as just royalist propaganda, particularly considering it only becomes a significant part of Charles II's biography thirty years after it supposed happend. But now Martin Lunn, the former curator of astronomy at England's Yorkshire Museum, thinks he's found evidence that this royal star really did exist, and it was actually a rather well-timed supernova.

Specifically, Lunn points to Cassiopeia A, a massive star that exploded about 11,000 light-years away, with the light of the explosion finally reaching Earth in the 1600s. These days, Cassiopeia A is no longer visible to the naked eye, as it's now just a faint X-ray source.

Back in the 17th century, however, it would have been a fantastic sight, and there are plenty of sources that suggest something like it was seen throughout the 1600s. These celestial sightings mostly cluster in dates after 1650, but Lunn and his research partner Lila Rakoczy believe the supernova could well have been visible on May 29, 1630, when Charles was born.

Their research is speculative and already fairly controversial, not least of which because, if they are correct, it means the current dating methods for supernova explosions need to be adjusted, as earlier calculations suggest Cassiopeia A was only visible later in the century. Lunn and Rakoczy's main proof is Britanniae Naturalis, a 1630 reference text written by 100 of Britain's top intellectuals, which among other things does indeed mention the star in connection to Charles II's birth earlier that year.

Lunn explains what this finding could mean:

"Our 1630 source forces astronomers to explain what was seen. Since other natural phenomena can easily be ruled out, that leaves a supernova as the most likely explanation, with Cas A becoming the most likely suspect. And if it is Cas A, then the current calibrations for distance need to be revisited."

So why didn't the star figure in royal propaganda before the restoration? Surely, a new star apparently attending Charles's birth would have been big news from the outset. The most likely explanation goes back to the historical context of the period - the monarchy was increasingly unpopular, and any astronomical portents were quickly forgotten as the United Kingdom slid into a bloody, ten-year civil war.

That, however, is hardly conclusive scientific evidence, as CalTech astronomer Mike Brown explains:

"It'll be interesting to see what the evidence is. If it could be shown that it appeared in the right spot in the sky at the right time, or if it could be shown to have been seen by many people distributed around the world — records of bright occurrences in the sky were pretty good by then — it would become convincing."

Lunn suggests he doesn't have that evidence yet, but he hopes to go through more archival evidence from 1630 for other records of a potential supernova. Since no supernovas were thought to have occurred at that time, astronomers haven't focused as much on such records, so Lunn is optimistic that he can find some proof that has previously been missed.

Ultimately, his hope is to show why astronomers and historians can benefit from working together:

"A lot more attention should be paid to archival collections from the 1630s, not just in Britain, but in countries around the world. Researchers out there might be coming across references to this star and not realize its potential astronomical significance. I see our role as adding new evidence to the impressive and important body of work already done, and hopefully getting the scientific community to reconsider some of their assumptions about their dating method."

Via Discovery News. Top image of Cassiopeia A today.